PARTIAL COALESCENCE IN OIL-IN-WATER EMULSIONS .1. NATURE OF THE AGGREGATION

被引:196
作者
BOODE, K [1 ]
WALSTRA, P [1 ]
机构
[1] AGR UNIV WAGENINGEN,DEPT FOOD SCI,6700 HB WAGENINGEN,NETHERLANDS
关键词
AGGREGATION; OIL-IN-WATER EMULSIONS; PARTIAL COALESCENCE;
D O I
10.1016/0927-7757(93)80239-B
中图分类号
O64 [物理化学(理论化学)、化学物理学];
学科分类号
070304 ; 081704 ;
摘要
The mechanism of aggregation in triglyceride oil-in-water (o/w) emulsions in which the droplets contain fat crystals was investigated. As a surfactant either sodium dodecyl sulphate (SDS) or a protein was used. The crystals must be situated at the o/w interface to cause partial coalescence; if the fat crystals are totally wetted by either the oil or the aqueous phase they do not affect emulsion stability. Although a suitable contact angle (crystal, oil, aqueous phase) appears necessary for partial coalescence to occur, it is obviously not a sufficient condition. Additional conditions are a close enough approach of the globules, allowing the protruding crystals to bridge the aqueous film between the globules, and the presence of sufficient solid fat. Crystals may have an approximately radial orientation at the o/w interface if they are kept in a continuous fat network. If, furthermore, the contact angle (as measured in the aqueous phase) is about 90-degrees, the coalescence efficiency a was high (mostly alpha much greater than 10(-6)). If crystals can move around freely in the oil droplet, they can obtain a tangential orientation at the interface irrespective of the contact angle. Such globules are not very sensitive to partial coalescence (alpha almost-equal-to 10(-6) or less). Even if partial coalescence had already occurred, it could in some cases be undone by changing the wetting properties so that the fat crystals become separated from the interface. This reversibility only held if the change occurred within a few hours after aggregation. After that the partially coalesced emulsion droplets had irreversibly merged into one bigger clump.
引用
收藏
页码:121 / 137
页数:17
相关论文
共 31 条
[1]  
ARCURI C, 1969, UNPUB
[2]   DESTABILIZATION OF O/W EMULSIONS CONTAINING FAT CRYSTALS BY TEMPERATURE CYCLING [J].
BOODE, K ;
BISPERINK, C ;
WALSTRA, P .
COLLOIDS AND SURFACES, 1991, 61 :55-74
[3]  
CAMPBELL I, 1989, FOOD COLLOIDS
[4]   THE AGGREGATION OF OIL PARTICLES IN EMULSIONS [J].
COCKBAIN, EG .
TRANSACTIONS OF THE FARADAY SOCIETY, 1952, 48 (02) :185-196
[5]   DILATOMETRIC STUDIES OF PURE TRIGLYCERIDES AND MIXTURES [J].
CRAIG, BM ;
LUNDBERG, WO ;
GEDDES, WF .
JOURNAL OF THE AMERICAN OIL CHEMISTS SOCIETY, 1952, 29 (04) :128-133
[6]   RECENT ADVANCES IN THE DESTABILIZATION OF DAIRY EMULSIONS [J].
DARLING, DF .
JOURNAL OF DAIRY RESEARCH, 1982, 49 (04) :695-712
[7]  
DEFEIJTER JA, 1987, COLLOID SURFACE, V27, P243, DOI 10.1016/0166-6622(87)80340-2
[8]   COMPETITIVE ADSORPTION OF MONOGLYCERIDES AND LECITHIN AT THE VEGETABLE OIL-WATER INTERFACE [J].
GAONKAR, AG ;
BORWANKAR, RP .
COLLOIDS AND SURFACES, 1991, 59 :331-343
[9]   RECENT DEVELOPMENTS IN THE UNDERSTANDING OF FOAM GENERATION AND STABILITY [J].
GARRETT, PR .
CHEMICAL ENGINEERING SCIENCE, 1993, 48 (02) :367-392
[10]  
HENING JC, 1932, TECH B NY AGR EXP ST, V197, P3